\begin{tikzpicture}
    \tkzDefPoints{0/0/A, 4/0/B, 0/1.5/C, 4/2.5/D}
    \tkzInterLL(A,D)(B,C)  \tkzGetPoint{E}
    \tkzDefLine[altitude](A,E,B)  \tkzGetPoint{F}

    \tkzDrawSegments(A,B A,C A,D B,C B,D E,F)
    \tkzLabelSegment[below](A,F){$m$}
    \tkzLabelSegment[below](F,B){$n$}
    \tkzLabelSegment[left](A,C){$p$}
    \tkzLabelSegment[right](B,D){$q$}
    \tkzLabelSegment[right](E,F){$r$}
    \tkzLabelPoints[left](A,C)
    \tkzLabelPoints[right](B,D)
    \tkzLabelPoints[above](E)
    \tkzLabelPoints[below](F)
\end{tikzpicture}

